It depends on each prefecture and time.
In particular, snow tires are needed in the mountain areas of Oita and Kumamoto, areas from Beppu to Aso, and Kurokawa Onsen area, etc. Even in other areas, if there is snow cover, snow tires are needed. Also, snow tires are needed from December to around April of the following year, but it varies depending on snow conditions, so please check the weather information for details.